Shelf



FIG. 1 is a perspective view of a shelf showing our new design.

FIG. 2 is a front view thereof, a rear view being a mirror image of the front view.

FIG. 3 is a left side view thereof, a right side view being a mirror image of the left side view.

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof.

The broken lines shown herein are for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a shelf, as shown and described. 